The present application is a continuation of Application Ser. No. 835,730 filed Sept. 22, 1977 now abandoned, which is a continuation-in-part of Ser. No. 657,619, filed Feb. 12, 1976, now abandoned.
Various prior art means are known to selectively guide a printed web of material, for example paper, from a supply roll to a take-up role past a selected location for viewing or other purposes. Such arrangements have been found, for example, in roll calendars.
Such prior art devices have not, however, provided means to deal with problems common encountered due to the elasticity of the web. More particularly, the elasticity of the printed web, and the inherent web tension in such prior art arrangements prevent efficient and proper indexing of the selected segments of the web in the viewing or work area intermediate the supply and take-up spindles. Specifically, such prior art devices do not provide efficient and economical arrangements whereby the web can be indexed to the proper location because of the tension inherent in the web. As a result, the web either "backs-up" or "rolls forward" when the take-up spindle is rotated to index a portion of the web in the work area and multiple adjustments are necessary to finally secure proper indexing.
A few prior art devices have provided complex, expensive arrangements to prevent web "back-up" or "roll forward" but such devices are prohibitively expensive and furthermore, even the arrangements provided by such prior art devices are not entirely satisfactory.